Apparatus for automatic grinding

ABSTRACT

A grinding wheel is moved to a reference position by a hydraulic piston, which carries a stepping motor therewith. The stepping motor advances the grinding wheel into the workpiece at varying rates and for various distances depending on the desired size of the workpiece. After completion of advancement of the grinding wheel into the workpiece, the grinding wheel may be retracted to a predetermined distance before dwell occurs.

FIG.

INVENTORS HOWARD W RENNER ROLF GRZYMEK ATTORNEY PATENIED Anal 7 l9?!SHEEY 02 0F 15 PATENTED M101 7 l97| SHEET 03 0F 15 PATENTED AUGI 712msaw on HF 15 FIG. 4

PATENTEU AusI H97! 3.599376 SHEET D7 0F 15 /|OO STOCK REMOVAL '09 /IO' YJ I MANUAL 0 CLE o3 SELECT I04 COARSE sTART I PIcKFEED HI INCREMENTFORWARD REVERSE CYCLE J MANUAL RA ID STOP I5I I55 7 PM P i sET SET MoToRMoToR RAP'D y FoRwARD REVERSE WHEELHEAD TO MACHINE FORWARD I I GRINDRETRAcT PosITIoN PosITIoN LIMIT sw. 73 LIMIT sw. 77

,. COARSE RATE souARE wAvE I T OSCILLATOR 1 /IO8 '07 RAPID RATE sQuAREWAVE HAS BEEN AMPLIFIER T OSCILLATOR SELECTED sET GAP ELIM. DOWN couNTMOTOR 7 RATE so. WAVE T PICKFEED cm. I FORWARD OSCILLATOR AND MoToR L L1 H2 SET PICKFEED STOP AT PICKFEED V PICKFEED COUNTER COUNTER ZERO I VsET STOCK W. STOP AT vA REMOVAL No. STOCK REMO L ZERO IN IN COUNTERCOUNTER couNTER I SET GAP ELIM. DowN couNT A MoToR RATE so. WAVE STOCKREM. cm.

REvERsE OSCILLATOR AND MoToR l RAPID u- WHEELHEAD TO MACHINE BACK FIG. 8

PATENTEU IuII I7 IIIII SHEET 08 0F 15 I00 STOCK REMovAL MED. FEED FINEFEED 5 H7 CYCLE |O9-\1-'nn [-1|] [Tn/H6 SELECTOR START ,1 l 4 l REV.FEEDCYCLE Ill STOP -L- I wEAR coMP. STOP L CONTINUOUS CYCLING RAPID RETRACTL WHEELHEAD TO MACHINE I CONTINUE SINGLE CYCLING CYCLE CONTINUE I IUNLESS IT Is I TIME TO TRUE I LOAD N0.oN sET To MACHINE wEAR COMP. WEARCOMP. PART DIGISW. No.

PART SET MOVE D I=RoM MAcI-IINE MOTOR wEAR COMP. LOADE FORWARD AMOUNT Ii l|2 RAPID WEAR GAP ELIM. wI-IE LIIEAD --To MAcI-IINE COMP. RATE SQUAREFORWARD COMPLETE WAVE osc.

DowN couNT WH AD EELHE GRIND PosITIo COUNTER FORWARD LIMIT SWITCH ANDMOTOR SET STOCK REMovAL AND fl 1 C I MOTOR NUMBER STOCK REMOVAL ouNTER0N AT 1 H8 DIGISWITCH I. NO. COUNTER ZERO OFF ON U (H2 GAP E GAP DOWNCOUNT R COUNTER V |M AT RATE SQ.WAVE EL m OR OSCILLATOR AND MOTOR I FIG.90 v I PATENTEU A1181 1 Ian SHEET 09 0F 15 I I I SURGE FINE FEED PARTNQHAS BEEN CONTACT MACH'NE REACHED I I |O6\ I L COARSE COARSE DOWN COUNTTIME RATE SQUARE COUNTER TO To RATE WAVE osc. AND MOTOR TRuE MACHINE Y UI MEDIUM MEDIUM DowN COUNT sET NO ON FEED NO.HAS --RATE SQUARE w COUNTERCOMP. COMPD BEEN REACHED wAvE osc. AND MoToR NUMBER DIGISWITCH I f I IFINE FEED FINE RATE DowN COUNT MovE SET NQHAS BEEN SQUARE couNTER COMP.MOTOR REAcHED wAvE osc. AND MOTOR AMOUNT FoRwARD i I24 ll2 REsET ND.COMP. AND GAP END U 0N STOCK TRUING ELRlxlgAsTgR FEED S WZII COMPLETEDwAvE osc j l27 T sET No. ON REVERSE TRUING DowN COUNT REvERsE REVERSEFEED No. COMPLETE COUNTER FEED NO. FEED DIGISW. couNTER FROM MACHINE ANDMDTDR sET COUNTER 7 MOTOR AT REVERSE ZERO ll2 I v AMPLIFIER RETRACT GAPELIM. DOWgJm8UNT REvERsE RATE so. FEED AMT. wAvE osc. ffim g 'g RF.COUNTER TARRY TIMER BETTA-I AT zERo T'MER OUT I Y I.

RETRAcT RAPID RATE DowN couNT MOTOR AND so. wAvE COUNTER WHEELHEAD TOMACHINE OSCILLATOR AND MOTOR I Ioa WHEELHEAD Fl .90

BACK AND UNLOAD To MACHINE G [MOTOR BACK PART F 9 b couNTED A35)ZCOUNTED A37 2 OUT ouT 9b PATENIEUAUBIIIBTI 3.5991376 sum 10 0F 1 STOCKREMOVAL MED. FEED 1 rloo GAGE CYCLE /H5 GRIND START SELECTOR L L COARSEFINE wEAR COMP H3 125 /-H| CYCLE STOP TRUING \I36 I COMPENSATION I33STOP SINGLE MULTI- m CON- m w TINUOUS CYCLE CYCLE q cYcLE 1 9 Q l34 II38 CONTINUE SINGLE CYCLE CYCLE [E I oAD T0 MACHINE P 22; FROM MACHINERAPID {E'fg TO MACHINE FoRwARD WHEEL- HEAD GRIND POSITION FORWARD LIMITSWITCH 73 |Io SET STOCK NUMBER COUNTER g5 gg N STOCK REMOVAL AT FORWARDDIGISW- COUNTER ZERO H8 k? I H 0 OFF ON GAP DOWN III II R 88KEREL'M'NATOR wAvE os. AND MOTOR I I I I I I I I FIG. HO

PATENTED AUG I 7 IQTI SHEET 1-1 0F 15 1 A II III I I II I I PART SURGEMED. FEED {SWITCH 0N NO HAS BEEN CONTACT MACHINE REACHED I I I I COARSEcoARsE RATE DOWN RATE so.wAvE COUNT OSCILLATOR fig ug Eg I I Ioe MED.FEED v NQ HAS BEEN AD ANCE TO MACHINE REAcHEo GAGE Y l GAGE FROMADVANCED MACHINE A06 coARsE DOWN COUNT I RATE so, '9' COUNTER FINE wAvE050. AND MOTOR l4l f ,E FINE RATE DOWN COUNTF" E so. WAVE COUNTER DWELL'43 2 4 osc. AND MTR. I42 I Ll/J44 TARRY TIMER I IIII BO TIMER 1 RETRAcTsET TO LOAD+TB E MOTOR POSITION REVERSE sET No. STOCK ON REM. No.DIGISW. 408 RETRAcT RAPID RATE DOWN COUNT T MOTOR 7 so. WAVE c uN ER TOzERo osc. AND MOTOR I WHEELHEAD RETRACT BACK AND GAGE T0 MACHINE MOTORBACK L UNLOAD I T0 MACHINE PART 135 I37 COUNTED -couNTEo a OUT 9 I OUTFIG. lOb

PATENTEU NIB I 7 IQII sum 12: 0F 15 SET MOTOR CONTINUE FORWARD IOUUNLESS ITIS TIME TO TRUE I FIG. lOc SET wEAR No.oN COMPENSATION WEARcoMR NUMBER DIGISW. FIG.

l {--I move GAP. ELIM. DOWN COUNT A wEAR coMP- RATE so. COUNTER AMOUNTwAvE osc. AND MOTOR G d I ll2 wEAR COMP. COMPLETE AMPLIFIER TIME T0---T0 MAcI-IINE TRUE i SET No. ON COMPENSATION COMP.

NUMBER DIGISWITCH SET I MOTOR FORWARD A 32 MOVE EI.IMI N A ToR cw?COMPENSAT'ON RATE so. COUNTER A AMOUNT wAvE osc. AND MOTOR I nz I 0CCOMPENSATION AND TRUING COMPLETE TRUING COMPLETE I FROM MACHINE PATENTEDIII; I 7 Ian SHEET 13 0F 15 PIcKFEED STOCK REMOVAL p INcREMENT '5] '50PICKFEED CYCLE GRIND sTART SELECTOR TRUING EAD PASS wEAR COMP.COMPENSATION TABLE REVERSAL ,III

CYCLE A54 STOP 136 1 I38 I {I33 |34\I I STOP SINGLE MULTI- CONTINUOUSCYCUNG CYCLE CYCLE CONTINUE SINGLE CYCLING CYCLE FEED SKIP TABLE J [NREvERsAI.

AFTER LOAD TO zERo MoToR STOP I PART T0 MACHINE GAP DOWN ELIMINATORcouNT SQUARE wAvE couNTER PART OSCILLATOR AND MoToR FROM MACHINE LOADEDH2 Y I RAPID w E TO MACHlNE FORWARD I l WHEELHEAD A 4 GRIND POSITION IIOFORWARD LIMIT SWITCH 73 I I I II SET NUMBER COUNTER E STOCK ON E STOCKREMOVAL AT SET f 'fmg k DIGISW couNTER ZERO PICKFEED I I I I INCREMENT fNUMBER ON DIGISW. ||8 I52 RESET PICKFEED couNTER PICKFEED INCREMENT ATINCREMENT couNTER ZERO OFF ON V I I VI PATENTEDAUBIHQH 3599376 SHEET 1n0F 15 CONTINUE sET H0 UNLESS IT I Is TIME MOTOR TO TRUE FORWARD I I cSET wEAR N0. ON wEAR FIG |b COMPENSATION COMPENSATION NUMBER 1DIGISWITCH MOVE wEAR GAP ELIM. DOWN COMPENSATION RATE so. SSKQE AMOUNTWAVE OSC. AhD MOTOR WEAR H2 COMPENSATION COMPLETE AMPLIFIER TIME f To ToMACHINE TRUE sET NUMBER COMPENSATIQN oN COMP.

NUMBER DIGISWITCH MovE sET COMPENSATION MOTOR AMOUNT FORWARD GAP DOWNELIMINATOR COUNT RATE so. coUNTER wAvE 050. AND MOTOR FIG. I I0COMPENSATION TRUING AND TRUING COMPLETE COMPLETE FROM MACHINE v PATENTEDAUG! 7 l9?! FIG. Ilb

SHEET 15 HF 15 i T T GAP GAP DOWN COUNT ELIMINATOR STOCK REM. ELIMINATORRATE so. COUNTER v 2/ wAvE 050 AND NoToR j sTo CK PART SURGE sw. REMOVALT couNTER ACT oN MACHINE AT ZERO WAIT FOR T TABLE TABLE REVERSAL REv.L.$. L.S. 0N MACHINE MOVE GAP DOWN STOP PICK FEED ELIMINATOR COUNT BOTHWHEN EITHER RATE so. couNTERs couNTER INCREMENT wAvE osc. AND MOTOR- ATzERo STOP FEED v sET pEAo NUMBER DEAD PASS COUNTER PASS TABLE 0N TABLEREV. AT

REVERSAL DIGISW. couNTER zERo Ty sET MoToR REVERSAL. RETRAcT I 12 -33 ToMACHINE 55 NUMBER REMOVAL" f I NUMBER DIGISW.

I08 RETRAcT RAPID DOWN C NT MOTOR To RATE $0. Egfi g ZERO WAVE OSC. ANDMOTQR WHEELHEAD UNLOAD BACK AND To MACHINE MOTOR BACK PART COUNTEDCOUNTED OUT ouT 9 F APPARATUS FOR AUTOMATIC GRINDING ln presentlyavailable grinding machines, a manual handwheel is normally connected tothe feed system of the machine. This requires a complicated and complexmechanism which has many mating members, thus reducing the overallrigidity of the feed system. The reduction of rigidity of the driveincreases the possibility that chatter may occur, for example, wherebydamage of the workpiece, which is being ground, would occur.Additionally, the lack of rigidity has an effect on the final size ofthe workpiece since the spring of the system increases with a reductionin rigidity.

The present invention satisfactorily solves the foregoing problem byutilizing a unique arrangement for the infeed mechanism for a grindingwheel. In the infeed mechanism of the present invention, a relativelysmall moment arm exists between the axis of the grinding wheel and theaxis of the feed screw. This is accomplished by eliminating anyrequirement for a manual handwheel to control movement of the grindingwheel toward and away from the workpiece. The present invention'utilizes an automatic control for movement of the grinding wheel towardand away from the workpiece so that the complicated structure of thehandwheel and its connecting means is eliminated.

In presently available grinding machines in which the manual handwheelis disposed at the front of the machine and the feed screw extendsrearwardly therefrom beneath the coolant trough, the feed screw mustpass through the support structure for the workpiece so that there isinterference therebetween. Accordingly, if a different type of supportstructure is required for the workpiece, substantial modification may berequired. In the present invention, the infeed mechanism is mounted onlyon the rear base of the machine so that it does not have any structureextending forward of the rear base. As a result, the present inventionpermits any type of support structure for the workpiece to be readilyutilized with the rear base, which has the infeed mechanism and thewheelhead supported thereon.

in presently available grinding machines, the grinding wheel is fed intothe workpiece at one or more different decreasing feed rates as thefinal size of the workpiece is approached. The grinding wheel must notbe fed into the workpiece the entire distance that it is desired toreduce the workpiece because of the windup or spring in the grindingmachine and workpiecesystem due to the feed force of the grinding wheelsince this windup or spring must be removed upon completion of grindingof the workpiece. Therefore, in presently available grinding machines,advancement of the grinding wheel into the workpiece is stopped short ofthe desired position to which it would be moved to obtain the finaldesired workpiece size. The grinding wheel is retained in this positionfor a period of time to finally finish the workpiece as the workpieceand the grinding wheel release their spring or windup due to thegrinding wheel no longer exerting a feed force on the workpiece.

In the present invention, the grinding wheel may be continuously fedinto the workpiece for the distance required to produce the finalsize-of the workpiece. Then, the grinding wheel is retracted from theworkpiece a predetermined distance before tarry or dwell occurs. Thus,when the grinding wheel is retracted from the workpiece, the windup orspring in the workpiece results in the workpiece remaining in engagementwith the grinding wheel so that the desired size and finish of theworkpiece is obtained. Therefore, the present invention reduces the timerequired to grind a workpiece and permits better control of the desiredsize and finish of'a workpiece than is presently available.

When utilizing an automatic grinding machine, the grinding wheel isnormally advanced from a reference position for its infeed. Since thesize of the grinding ,wheelreduces as wear occurs, it is desirable to beableto-compensate for this wear at various times before truing of thegrinding wheel is required.

The present invention satisfactorily meets this problem by includingmeans to automatically compensate for wear of the grinding wheel so asto change the reference position from which the grinding wheel is fedinto the workpiece. Therefore more uniformity of the size of thefinished workpieces, which are produced by the automatic grindingmachine of the present invention, is obtained than has been previouslyavailable.

Instead of changing the feed rate of the grinding wheel toward theworkpiece at various predetermined, distances from the referenceposition, the feed rate of the grinding wheel toward the workpiece maybe controlled by a gage. This gage would stop the final feed rate of thegrinding wheel toward the workpiece when the gage indicates that theworkpiece is of the desired size. Thus, instead of relying uponpredetermined distances from a reference position for obtaining thedesired final size of the workpiece, the present invention permits theutilization of a gage for automatically controlling when the final sizeof the workpiece is reached.

An object of this invention is to provide an apparatus for automaticallygrinding a plurality of workpieces to substantially the same size.

Another object of this invention is to provide a unique infeed mechanismfor a grinding wheel.

Other objects of this invention will be readily perceived from thefollowing description, claims, and drawings.

This invention relates to a mechanism for producing relative movementtoward and away from each other between a grinding wheel and aworkpiece. The invention includes a feed member adapted to be connectedto one of the support means for the workpiece and a wheelhead or thelike on which the grinding wheel is supported and fluid-responsivemeans. Means, which is connected to the feed member and to thefluid-responsive means, moves the feed member both independently of thefluid-responsive means and simultaneously therewith. Thefluid-responsive means moves the feed member at a faster rate than theconnected means with the connected means being movable with thefluid-responsive means to move the feed member.

This invention also relates to a mechanism for controlling the grindingof a workpiece by a grinding wheel. The mechanism includes means to feedone of the grinding wheel and the workpiece toward the other whereby oneof the grinding wheel and the workpiece is a movable member and theother of the grinding wheel and the workpiece is a fixed member. Thefeed means feeds the movable member for a predetermined distance from areference position with means to automatically stop feeding by the feedmeans when the movable member has been advanced toward the fixed memberthe predetermined distance from the reference position. Means retractsthe movable member a predetermined distance after the stop means isactuated with the grinding wheel and the workpiece remaining inengagement with each other in the retracted position of the movablemember. The movable member is held at the retracted position for apredetermined period of time by suitable means.

This invention further relates to a mechanism for controlling thegrinding of a workpiece by a grinding wheel including means to feed oneof the grinding wheel and the workpiece toward the other whereby one ofthe grinding wheel and the workpiece is a movable member and the otherof the grinding wheel and the workpiece is a fixed member. The feedmeans feeds the movable member from a reference position with means tomeasure the size of the workpiece being ground. The measuring means hasmeans to reduce the feed rate of the feed means when the workpiece hasbeen reduced to a predetermined size by the grinding wheel as determinedby the measuring means. Feeding of the movable member by the feed meansis stopped by suitablemeans when the workpiece has further been reducedby the grinding wheel as determined by the measuring means.

This invention still further relates to a grinding machine includingfront and rear bases connected to each other with a grinding wheelmounted on the rear base by suitable means for movement relative to therear base. The front base has workpiece support mans mounted thereon andthe grinding wheel is moved toward and away from a workpiece on theworkpiece support means by feed means, which is supported only on therear base.

The attached drawings illustrate a preferred embodiment of theinvention, in which:

FIG. 1 is a sectional view, partly in elevation, of the automaticgrinding machine of the present invention showing the infeed mechanism;

FIG. 2 is an end elevational view of a portion of the automatic grindingmachine of the present invention including the infeed mechanism;

FIG. 3 is a sectional view taken substantially along line 3-3 of FIG. 2;7

FIG. 4 is a side elevational view of a portion of the structure of FIG.and taken from the left side of FIG. 2;

FIG.'5 is a side elevational view of the structure of FIG. 2 and takenfrom the right side of FIG. 2;

FIG. 6 is an enlarged sectional view, partly schematic, of a portion ofthe structure of FIG. 2 and showing the fluid arrangement for rapidmovement of the wheelhead;

FIG. 7 is an enlarged sectional view of a clutch for connecting the feedscrew to a motor;

FIG. 8 is a schematic diagram illustrating the logic when the automaticgrinding machine is in the manual mode;

FIGS. 9a and 9b are schematic views illustrating the logic of theautomatic grinding machine whenthe automatic grinding machine is in aplunge grind mode:

FIG. 90 is a schematic view illustrating the arrangement of FIGS. 9a and9b;

. FIGS. 10a10c are schematic views illustrating the logic when theautomatic grinding machine of the present invention is in a gage grindmode;

FIG. 10d is a schematic view illustrating the arrangement of FIGS.10a10c;

FIGS. l1a-1lc are schematic views illustrating the logic when theautomatic grinding machine of the present invention is in a pickfeedgrind mode; and

FIG. 1 1d is a schematic view illustrating the arrangement of FIGS.l1a--11c.

Referring to the drawings and particularly FIG. 1, there is shown anautomatic grinding machine of the present invention. The automaticgrinding machine of the present invention includes a'grinding wheel 10,which is rotatably mounted on a wheelhead 11. The wheelhead 11 isadapted to be moved along ways 12 (see FIG. 2) in a rear base 14 of thegrinding machine of the present invention.

The grinding wheel 10 is adapted to be advanced into engagement with aworkpiece 15, which is mounted between a headstock l6 and a tailstock(not shown), for example. The headstock 16 and the tailstock aresupported on a swivel table 17, which is swivelly mounted on a slidingtable 18. The sliding table 18 is mounted on ways 19 of a front base 20for movement transversely to the grinding wheel 10.

The front base 20 and the rear base 14 form the machine base of thepresent invention. Each of the front and rear bases is readily usablewith other bases since the structure supported by each is completelyseparate.

The infeed mechanism for moving the grinding wheel 10 into and away fromgrinding engagement with the workpiece 15 includes a feed screw 21,which is connected to the wheelhead 11 through a feed or ball nut 22, aplate 23 (see FIG. 3), and a substantially U-shaped bracket 24. Thebracket 24, which is fixedly secured to the wheelhead 11 by screws 25,has the plate 23 secured thereto by screws 26. Since the plate 23 hasthe ball nut 22 secured thereto by screws 27, the feed screw 21 isconnected to the wheel head 1 1 for causing movement thereof along theways 12.

The ball nut 22 comprises a pair of nuts 28 and 29, which are spacedfrom each other by a spacer 30 that determines the preload on the nuts28 and 29. The nuts 28 and 29 and the spacer 30 are secured to eachother by the screws 27, which also connect the ball nut 22 to the plate23.

This arrangement allows the feed screw 21 to be rotatably movablerelative to the feed nut 22 to transmit its rotation into axial movementof the wheelhead 11. The arrangement also allows axial movement of thewheelhead 11 by the feed screw 21 when it is axially moved by ahydraulic piston 31 (see FIG. 3).

The feed screw 21 is rotatably driven by a stepping motor 32 through areducing unit 33. One suitable example of the stepping motor 32 is theelectric stepping motor sold by Superior Electric Company as TypeI-ISSO. One suitable example of the speed-reducing unit 33 is sold byUnited Shoe Machinery Company as Model HDUC-ZO-IOO. It should beunderstood that the speed-reducing unit 33 may be formed with variousratios of speed reduction depending upon the type of machine upon whichthe workpiece is to be ground.

The stepping motor 32 is carried on one end of the movable hydraulicpiston 31, which is slidably disposed in a chamber 33' (see FIG. 6)within a hydraulic cylinder housing 34. The hydraulic cylinder housing34 is fixedly secured against move ment by being secured to the rearbase 14 by ears 35 (see FIG. 2) on the cylinder housing 34 beingconnected to ears 36 on the rear base 14 by screws 37.

Thus, whenever the hydraulic piston 31 is advanced from the position ofFIG. 3, the wheelhead 11 will be moved along the ways 12 so that thegrinding wheel is moved toward the workpiece 15. Thus, the hydraulicpiston 31 allows a rapid ad vance of the grinding wheel 10 to areference position, which is selected by the operator, from which thestepping motor 32 may be employed for advancing the grinding wheel 10into engagement with the workpiece 15 at the desired feed rate. Thestepping motor 32 is secured to the piston 31 through a 'sup port 38,which is secured to the end of the piston 31 by screws 39. The steppingmotor 32 is fixed to the support 38 by screws 40.

The support 38 carries a pair of cam rollers 41 and 42 on its flange 43.The cam rollers 41 and 42 ride on opposite sides of a rail 44, which issupported by the hydraulic cylinder housing 34. Thus, the cam rollers 41and 42 and the rail 44 insure that any rotation of the feed screw 21 bythe stepping motor 32 is transformed into axial motion of the wheelhead11 and the grinding wheel 10. Furthermore, the cam rollers 41 and 42cooperate with the rail 44 to insure that only axial movement of thehydraulic piston 31 occurs when the hydraulic piston 31 is actuated.

In addition to rotation of the feed screw 21 by the stepping motor 32,the'feed screw 21 also may be rotated by an AC induction motor 45, whichis supported on the rear base 14. The induction motor 45 drives thewheelhead 11 at a more rapid rate than is available with the steppingmotor 32. The motor 45 has its output shaft connected through a shaft45a having flexible couplings therein to a vertically disposed shaft45b, which is rotatably supported by the base 14, through a worm 450 onthe shaft 45a and a worm wheel 45d on the lower end of the shaft 45b.Accordingly, the motor 45 rotates the shaft 451:.

The upper end of the shaft 45b has a bevel gear 46 mounted thereon formeshing with a bevel gear 46a, which is secured to an annular member 46b(see FIG. 7). The member 46b is secured to a member 46c having a thinannular section 46d forming a 'wall of a recess 46e within the members46b and 46c. Fluid is supplied to the recess 46e through an annularpassage 46f, which is in communication with a source of fluid underpressure, in the member 46b.

The member 460 is mounted in surrounding relationship to a bushing 47,which has splines on its inner surface for cooperation with a splinedshaft 48. When fluid is supplied to i the recess 46e, the thin annularsection 46d is deflected inwardly to grip the bushing 47 and causerotation of the shaft 48 through the splined, connection on the shaft 48and in the bushing 47.

Whenever there is no fluid pressure in the recess 46c, the torque motor45 cannotrotate the feed screw 21. However, rotation of the feed screw21 by the stepping motor 32 can occur and result in the splined shaft 48rotating without any effect n the drive from the motor 45 since the thinannular section 46d is not gripping the bushing 47. Additionally, thebushing 47 allows axial movement of the feed screw 21 and the splinedshaft 48 relative thereto when the wheelhead 11 is ad- .vanced by thepiston 31.

It should be understood that the logic circuit of the present inventionprevents actuation of the motor 45 if the motor 32 is energized and viceversa. Thus, there can be no inadvertent attempt by the motors 32 and 45to simultaneously drive the feed screw 21.

The actuation of the hydraulic piston 31 is controlled through asuitable fluid system. The system includes a pump 50, which suppliesfluid from a reservoir 50', connected to an inlet port of a valve 51,which is controlled by a solenoid 52. When the solenoid 52 is notenergized, the valve 51 is disposed in the position shown in FIG. 6whereby the pump 50 communicates through the valve 51 with a line 53,which leads to a valve 54. The valve 54 is disposed in the position ofFIG. 6 when a solenoid 55, which controls the position of the valve 54,is not energized. In the position of the valves 51 and 54 as shown inFIG. 6, the fluid is supplied from the pump 50 to cause retraction ofthe piston 31 so as to retract the grinding wheel rapidly away from theworkpiece 15. This fluid is supplied from the'pump 50 through a line 56to the interior of the housing 34 to act on the piston 31.

When it is desired to advance the grinding wheel 10 toward the workpiece15, the solenoid 55 is energized whereby the fluid from the pump 50 issupplied through a line 57 to the interior of the hydraulic cylinderhousing 34. This acts on the piston 31 to rapidly move the grindingwheel 10 toward the workpiece 15. However, the amount. of movement ofthe piston 31 is such that the grinding wheel 10 is not moved intoengagement with the workpiece 15. i

As shown in FIG. 6, the piston 31 is beveled at each end. Accordingly,when fluid is supplied through the line 57 to advance the grinding wheel10 toward the workpiece 15, the fluid passes from the line 57 through achamber 58 in the housing 34, a line 59, a valve 60, and a line 61. Asthe piston 31 advances through the chamber 33' in the housing 34 to theright as shown in FIG. 6, the fluid on the right side of the piston 31exits therefrom through a line 62, a valve 63, and the line 56.

As soon as the solenoid 55 is energized, fluid under pressure issupplied to the line 57 and to the left side of a freely movable piston69, which is disposed within the chamber 58 in the housing 34. Becausethe chamber 58 communicates with the line 56 through a line 75, theright side of the piston 69 is exposed to exhaust pressure. Thus, asfluid is applied to the left side of the piston 69, the piston 69 isdriven to the right to allow fluid to pass through the lines 59 and 61to the left side of the piston 31.

As the piston 31 approaches the end of the chamber 33' in the housing 34in which it is movable, it gradually closes the line 62 causing thewheelhead 11 to be decelerated. After the line 62 is closed by thepiston 31, the fluid exits from the chamber 33 through a line 64 intothe valve 63. The line 64 communicates with the line 56 through a ballvalve 65, which forms part of the valve 63, and is resiliently biased bya spring 66 into engagement with one end of a threaded stud 67. Byadjusting the position of the threaded stud 67, the position of the ballvalve 65 within housing 68 of the valve 63 is changed.

Thus, the position of the threaded stud 67 in the valve housing 68regulates the final approach rate of movement of the piston 31 as itcompletes its advance movement.

A control rod 70, which is slidably mounted within the housing 34, has aclamping ring 71 adjustably mounted thereon. The clamping rod 71 isengaged by a member 72, which is carried by the support 38 so as to bemovable with the piston 31. Thus, as the piston 31 advances to the rightin FIG. 6, the member 72 on the support 38 engages the clamping ring 71and starts movement of the control rod 70. This moves the rod 70 intothe chamber 58 as indicated in dotted lines.

When the piston 31 completes its forward movement, a switch 73, which iscarried on the housing 34, has its arm 73' engaged by a pin 74 (see FIG.4) on the support 38. This indicates to the logic circuit of the presentinvention that the piston 31 has completed its forward movement and thestepping motor 32 may now be energized.

When it is desired to retract the piston 31 from its forwardmostposition, the solenoid 55 is deenergized to change the position of thevalve 54 to allow fluid to be supplied to the chamber 33' through theline 56 and exhausted from the chamber 33' through the line 57. Thefluid initially enters the chamber 33' by flowing form the line 56 pastthe ball valve 65 in the valve housing 68 into the line 64. This resultsin the fluid acting on the beveled portion of the piston 31. i

As the piston 31 is retracted by the pressurized fluid, the line 62is'uncovered. As a result, the fluid flow past the ball valve 65 andthrough the line 64 becomes negligible.

As the piston 31 retracts, the fluid flows from the chamber 33 throughthe line 61, the valve 60, and the line 59 to the chamber 58 and thenthrough the line 57. At this time, the piston 69 is not disposed in thesolid line position of FIG. 6. However, the chamber 58, which has thepiston 69 therein, is receiving fluid from the line 56 through the line75, which provides communication from the line 56 to the chamber 58.Therefore, fluid pressure acts on the right side of the piston 69 tocause it to move the control rod 70 to the left. The amount of movementof the control rod 70 by the piston 69 is limited by the clamping ring71 engaging the member 72 on the support 38. Since the member 72 ismoving with the piston 31, the piston 69 cannot move the control rod 70any further than the piston 31 has moved. i

As the piston 31 retracts, the control rod 70 is continued to be movedby the piston 69 until the piston 69 blocks the line 59 fromcommunication with the line 57. When this occurs, fluid exhausting fromthe chamber 33 through the line 61 is stopped so that retraction of thepiston 31 by fluid entering the chamber 33' from the line 56 is stopped.Therefore, as soon as the piston 69 blocks the line 59 fromcommunicating with the line 57, retraction of the piston 31 is stopped.

The piston 69 has its left end beveled so that the flow from the line 59to the line 57 is cut off smoothly. Thus, a smooth deceleration of thepiston 31 occurs.

When the retraction of the piston 31 is stopped, a switch 76, which iscarried by the housing 34, is actuated through having its arm 77 engagedby a clamping ring 78; the ring 78 is mounted on the control rod 70 onthe opposite side of the member 72 from the ring 71. The actuation ofthe switch 76 provides a signal to the logic circuit of the grindingmachine to indicate that retraction of the piston 31 has stopped. Thisresults in energization of the solenoid 52 to move the valve 51 to aposition in which the fluid on each side of the piston 31 is trappedtherein so as to prevent any further movement of the piston 31.

Whenever it is desired to reduce the amount of retraction of the piston31, it is only necessary to move the clamping ring 71 to the right. As aresult, the control rod 70 will not be moved by the piston 31 as far tothe right during its advancement. Thus, the piston 69 does not have tomove as far to the left to block the line 59 from communication with theline 57 during retraction.

When it is desired to retract the piston 31 the complete length of thechamber 33', it is necessary to prevent fluid flow from the line 56 intothe chamber 58 through the line 75. To accomplish this, the line 75 hasa plug 79 therein to cause the fluid flowing through the line 75 to haveto pass through a valve 80, which is controlled by a solenoid 81. Duringnormal operations, the solenoid 81 is deenergized to allow flow throughthe line 75. Y When it is desired to retract the piston 31 the entirelength of the chamber 33, the solenoid 81 is energized whereby the line75 no longer provides communication from the line 56 to the chamber 58.As a result, the piston 69 is not moved by fluid pressure to blockcommunication between the lines 57 and 59.

Therefore, fluid continues to escape from the chamber 33 through theline 61, the valve 60, and the line 59 to the line 57 until the line 61is blocked by the piston 31. When the line 61 is blocked, a line 82,which communicates with the line 59 through a passage in housing 84 ofthe valve 60 in which a ball valve 83 is disposed, has fluid flowingtherethrough to the line 59. The position of the ball valve 83, which isresiliently biased against one end of a threaded stud 85 by a spring 86,is adjusted by the threaded stud 85 in the housing 84 to regulate thefinal approach rate of movement of the piston 31. It should be notedthat the left side of the piston 31 is beveled in the same manner as theright side to aid in deceleration of the piston 31 during fullretraction.

When the piston 31 is completely retracted, this position of the piston31 is indicated to the logic circuit of the present invention throughactuating a switch 87 (see FIG. 4), which is supported on the housing34, by having its arm 88 engaged by the pin 74 on the support 38, whichis carried with the piston 31. This allows the logic circuit to proceedwith the additional operations of the grinding process.

In order to limit rearward movement of the feed screw 21, a limit switch89 (see FIG. 2) is mounted on the support 38 by a bracket 90. When aroller 91 on an arm 92 of the limit switch 89 is engaged by a setscrew93 on the wheelhead 11, the limit switch 89 indicates this to the logiccircuit and stops further rearward movement of the stepping motor 32 orthe motor 45. Accordingly, neither the stepping motor 32 nor the motor45 can be energized to cause further rearward movement of the feed screw21 once the switch 89 has been actuated.

Forward movement of the feed screw 21 is stopped by a limit switch 94,which is mounted on the support 38 by a bracket 95. When a roller 96 onan arm 97 of the switch 94 is engaged by a block 97' on a rod 98, whichis supported by the wheelhead 1 l, the switch 94 is actuated to indicateto the logic circuit that forward movement of the feed screw 21 must bestopped. Accordingly, neither the stepping motor nor the motor 45 can beenergized to cause further forward movement of the feed screw 21 oncethe switch 94 has been actuated. The rod 98, which is supported withinpassages in cars 99 and 990 (see FIG. on a flange 99b of the bracket 95,is actuated by the wheelhead 11 when the feed screw 21 has been advancedthe permissible maximum by the stepping motor 32 or the motor 45. Whenthe rod 98 is moved by the wheelhead 1 1, the block on the rod 98actuates the switch 94.

It should be understood that a spring 990, which surrounds the rod 98between the ears 99 and 99a, continuously urges the block 97' on the rod98 away from the roller 96. Thus, after the switch 94 is actuated,rearward movement of the wheelhead 1 1 results in the block 97 on therod 98 ceasing to engage the roller 96 due to the force of the spring990.

The infeed mechanism of the present invention may be readily utilizedfor plunge grinding, gage grinding, or pickfeed grinding. The logic ofthe grinding machine permits utilization of these various cyclesautomatically. The operation of the grinding machine of the presentinvention will be described through schematic diagrams to indicate thelogic circuits whereby the various automatic grinding cycles may becarried out.

Referring to FIG. 8, there is shown a schematic block diagram of thelogic circuit employed in a manual mode whereby a desired or selectedreference position of the stepping motor 32 for each cycle will bedetermined. After a manual select button 101 is pushed to select themanual mode, actuation of'a cycle start button 100 advances the grindingwheel rapidly toward the workpiece through causing fluid to be suppliedto the chamber 33 to act on the piston 31 to advance the piston 31.Thus, actuation of the button 100 causes deenergization of the solenoid52 (see FIG. 6) and energization of the solenoid 55 whereby the piston31 maybe rapidly advanced.

When the grinding wheel 10 has been advanced as far as is possible bythe piston 31, this is indicated to the logic circuit by the actuationof the switch 73. Only after the switch 73 is actuated can the steppingmotor 32 be moved to cause forward movement of the grinding wheel 10toward the workpiece or part 15.

In the manual mode, only the coarse rate and rapid rate of movement ofthe stepping motor 32 are utilized and available for moving the grindingwheel 10. While the stepping motor 32 may be moved at medium and finefeed rates, these feed rates are not available in the manual mode. Thestepping motor 32 is moved at the rapid rate, which is faster than thecoarse rate, by actuating a rapid button 102.

When the manual select button 101 is actuated, the stepping motor 32 maybe moved either in a forward or reverse direction through pushing aforward button 103 or a reverse button 104. Since the manual mode isused to set up the movement of the machine for the automatic modes ofthe present invention, the forward button 103 is normally movedinitially. This sets the stepping motor 32 in a forward direction butthe logic circuit does not permit actuation of the stepping motor 32until the switch 73 has been actuated to indicate that the grindingwheel 10 is positioned for grinding; this is indicated in FIG. 8 by ablock 105.

Thus, when the switch 73 has been actuated to indicate that the piston31 has completed advance movement, then the stepping motor 32 may bemoved at either the coarse rate or the rapid rate. A coarse rate squarewave oscillator 106 is energized whenever the forward button 103 ispushed if the switch 73 has been actuated. The output of the square waveoscillator 106 is supplied through an amplifier 107 to the steppingmotor 32 to cause the 'forward stepping of the stepping motor 32 at thecoarse rate. When the rapid button 102 is actuated along with theforward button 103, the stepping motor 32 is advanced at a more rapidrate due to energization of a rapid rate square wave oscillator 108.

The stepping motor 32 remains energized by holding the forward button103 actuated until the grinding wheel 10 has engaged the workpiece 15sufficiently to clean up the workpiece or part 15 so that it may bemeasured for size. Then, a stock removal thumbwheel switch 109 has adesired amount of stock removal set thereon and on a stock removalnumber counter 110.

A cycle stop button 111 is then pushed to cause rapid retraction of thegrinding wheel 10 away from the workpiece 15. This is accomplishedthrough the button 111 causing deenergization of the solenoids 55 and 52(see FIG. 6) through the logic circuit. At the same time, the cycle stopbutton 111 causes the logic circuit to set the stepping motor 32 to runin the reverse direction, set in the stock removal distance from theswitch 109, and run the stepping motor 32 at a frequency of a gapeliminator rate square wave oscillator 112 until the counter reacheszero. Now the size of the workpiece 15 is determined and any additionalrequired reduction in size of the workpiece is added to the stockremoval switch 109. Thus, during an automatic mode, the stepping motor32 is advanced from the selected reference position, which is where itis now positioned, not only the original amount that was placed on thestock removal switch 109 but also the amount that was added by theoperator.

In the manual mode of operation, the coarse rate at which the steppingmotor 32 is fed may be changed through movement of a coarse dial 113.This alters the output of the coarse rate square wave oscillator 106through changing the value of a potentiometer in the oscillator 106.

After the stock removal switch 109 has had the desired amount ofmovement of the stepping motor 32 from its reference position, which hasbeen selected due to the initial amount that the stepping motor 32 wasbacked off from the workpiece 15 after cleaning up the workpiece 15,registered thereon by the operator, automatic plunge grinding of theworkpieces or parts 15 may be accomplished through utilizing the logiccircuit of-the present invention as indicated in FIGS.

1. A mechanism for producing relative movement toward and away from eachother between a tool of a machine tool and a workpiece comprising: afeed member; fluid-responsive means including: a housing having achamber therein; and a piston disposed in said chamber in said housingto produce relative translational movement between said housing and saidpiston when fluid is supplied to said chamber; said piston having meansto rotatably support said feed member; first means connecting saidpiston to said feed member; said first connecting man including motivemeans to rotate said feed member relative to said fluid-responsivemeans; means to prevent relative rotation between said motive means andsaid housing; said means to connect one of said feed member and saidhousing to the movable one of the workpiece and the tool and to connectthe other of said feed member and said housing to a fixed structure; andsaid second connecting means including means to convert rotationalmovement of said feed member to translational movement of the movableone of the workpiece and the tool; said motive means rotating said feedmember both independently of movement of the movable one of said pistonand said housing due to fluid supplied to said chamber andsimultaneously therewith.
 2. The mechanism according to claim 1including means to regulate the rate of movement of saidfluid-responsive means.
 3. The mechanism according to claim 1 in which:said fluid-responsive means and said motive means are mountedconcentrically with said feed member; and said fluid-responsive means isin surrounding relation to a portion of said feed member.
 4. Themechanism according to claim 1 in which said motive means is a steppingmotor.
 5. The mechanism according to claim 1 in which: said secondconnecting means includes: means to connect said feed member to themovable one of the workpiece and the tool; and means to connect saidhousing to the fixed structure; and said feed member both rotates andtranslates simultaneously or independently to impart movement to themovable one of the workpiece and the tool.
 6. The mechanism according toclaim 5 including: drive means adapted to be connected to said feedmember for moving said feed member independently of said motive meansand said fluid-responsive means; and means to selectively connect saiddrive means to said feed member, said drive means moving said feedmember at a faster rate than said motive means but a slower rate thansaid fluid-responsive means.
 7. A mechanism for controlling the grindingof a workpiece by a grinding wheel including: mean to feed one of thegrinding wheel and the workpiece toward the other whereby the one of thegrinding wheel and the workpiece is a movable member and the other ofthe grinding wheel and the workpiece is a fixed member, said feed meansfeeding the movable member for a predetermined distance from a referenceposition; means to automatically stop feeding by said feed means whenthe movable member has been advanced toward the fixed member thepredetermined distance from the reference position; means to retract themovable member a predetermined distance after said stop means isactuated, the grinding wheel and the workpiece remaining in engagementwith each other in the retracted position of the movable member; andmeans to hold the movable member at the retracted position for apredetermined period of time.
 8. The mechanism according to claim 7including means to move the reference position a predetermined distancecloser to the fixed member after a predetermined number of theworkpieces has been ground.
 9. The mechanism according to claim 7including means to rapidly move the movable member to the referenceposition.
 10. The mechanism according to claim 7 including means to varythe predetermined distance that said retracting means retracts themovable member.
 11. The mechanism according to claim 7 including meansto vary the predetermined period of time during which said holding meansis effective.
 12. The mechanism according to claim 7 in which: said feedmeans comprises: motive means; and speed-reducing means.
 13. Themechanism according to claim 12 in which said motive means is a steppingmotor.
 14. A mechanism for controlling the grinding of a workpiece by agrinding wheel including: means to feed one of the grinding wheel andthe workpiece toward the other whereby the one of the grinding wheel andthe workpiece is a movable member and the other of the grinding wheeland the workpiece is a fixed member, said feed means feeding the movablemember from a reference position; means to measure the size of theworkpiece being ground; said measuring means having means to reduce thefeed rate of said feed means when the workpiece has been reduced to apredetermined size by the grinding wheel as determined by said measuringmeans; means to stop feeding of the movable member by said feed meanswhen the workpiece has further been reduced by the grinding wheel asdetermined by said measuring means; means to retract the movable membera predetermined distance after said stop means is actuated, the grindingwheel and the workpiece remaining in engagement with each other in theretracted position; and means to hold the movable member at theretracted position for a predetermined period of time.
 15. The mechanismaccording to claim 14 including means to vary the predetermined periodof time during which said hold means is effective.
 16. The mechanismaccording to claim 5 in which said means connecting said feed member tothe movable one of the workpiece and the tool includes means tosimultaneously transfer the translation and rotational movement of saidfeed member to translational movement of the movable one of theworkpiece and the tool.
 17. The mechanism according to claim 1 in which:said motive means is connected to said piston; said first connectingmeans includes means connecting said motive means to said feed member;and said preventing means prevents rotation of said motive means andsaid piston relative to said housing when said motive means isactivated.
 18. The mechanism according to claim 17 in which saidconnecting means connecting said motive means to said feed memberincludes speed-reducing means.
 19. The mechanism according to claim 1 inwhich said motive means comprises means to rotate said feed member ineither direction.
 20. The mechanism according to claim 19 includingmeans to limit the rotation of said feed member in either direction bysaid motive means in accordance with the relative position between theworkpiece and the tool.
 21. The mechanism according to claim 1 includingmeans to selectively change the rate of rotation of said feed member bysaid motive means during movement of the movable one of the workpieceand the tool.
 22. The mechanism according to claim 1 including means toselectively control the amount of relative translational movementbetween said housing and said piston.